Not easy calculations

Hi i have a couple of questions which are very important :)
SO my approach looks like that when i see on the ils that i have to go down i put my speed to 200 knots, flaps 1 (my altutide is often 12k f) then when im at 8k f i put the speed to 190 knots flaps 5 and when im at 3k f i put my speed to 160 knots then when i have 4 Miles to dest i put the landing speed i mean the speed for the aircraft to land
And is IT bad ? Cuz ive seen peoples which fly with more Thank 190 knots at 8 k f
Next question is how to calcutlate the cruise altutide for example i have 126 Miles to dest so what altutide i should have ?

Don’t use flaps so early at least.
I usually put speed 210-225 knots at 4,000-5,000 and flaps 5 at the same time.
Some wiser people might have better answers though.

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If I understand what you’re saying, you extend flaps to full at 210-225kts. I would say that’s too fast and would likely damage the flaps. Full flaps is usually only used when on final and travelling at final approach speed. If I’ve misunderstood your meaning, I apologise.

Was that reply meant for me?
If so I don’t do that, I meant that put flaps 5 degrees (On Boeing planes) at 210 AS.

Flaps look about right, at 3000ft you may find it easier to disengage autopilot and hand fly. I use:

5 degree below 6000
10/15 8-10 miles out
20 6-8 miles out
Landing 25/30 5 miles out, with gear and spoilers armed

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I start slowing and deploying flaps around 5k. Gradually slowing, you should be at around 180 kts and flaps 15-20/2-3 at the ILS intercept/10 mi out. Slow to vapp around 7 miles, and fully configured by 5 miles. If I’m not configured by 1000 ft AGL, then it’s a missed approach.

Oh sorry, I’m confusing myself (it doesn’t take much).

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Generally it depends on several factors such as the aircraft type, weight, approach type (stabalized vs. decelerated) and also restrictions provided by the relevant approach chart.

I will eleborate on this for Boeing and Airbus seperatley.

Boeing uses the Vref30 speed as reference for each flap setting to manage the the flap extension schedule. The safe flap maneuvering speeds are:

Flaps Up: Vref30 + 80kts
Flaps 1: Vref30 + 60kts
Flaps 5: Vref30 + 40kts
Flaps 15/20: Vref30 + 20kts
Flaps 25: Vref30 + 10kts
Flaps 30: Vref30 + 5kts (Vapp) without adjustment for headwind component

This means that when you reach Vref30 + 80kts, select flaps 1 and reduce speed to Vref30 + 60kts, then select flaps 5 and reduce speed to Vref30 + 40kts. Notice that you are always within the safe flap maneuvering speed? Now continue to extend flaps as described above until reaching flaps 30 at wich you reduce speed to Vapp.

Here an example: For the 777-200/LR with a weight of 450 000 lbs or 205 000 kg (as used in IF, the Vref30= 135 kts. This means that when you reach 215 kts (Vref30 + 80 = 135 + 80= 215kts) set flaps 1 before reducing speed further. This is because a speed lower than 215kts is no longer within the safe maneuvering speed for flaps “up” or clean configuration. Once flaps are set to 1, reduce your speed to 195kts (Vref30 + 60 = 135 + 60 = 195kts) and maintain this speed. Now set flaps to 5 and reduce your speed to 175kts (Vref30 + 40 kts). Then set flaps to 20 (Flaps 15 is only used for Takeoff!) and reduce speed to 155kts (Vref30 + 20). And finally set flaps to 30 and reduce speed to Vapp. Flaps 25 can be used for landing especially during heavy turbulence landings but that i’d rather discuss this in a different topic. These rules also apply to the 787. For a 787 with a weight of 172 000kg, Vref30 is 142kts.

For the Airbus A320 Family, flap extension and retraction schedules are based on the respective S (Slats) and F (Flaps) speed. These can be calculated based on VLS (lowest selectable speed) for a given configuration:

S speed= 1.21 VLS for clean configuration
F speed= 1.18 VLS for Config 1+ F

This means that before reducing speed to lower than S speed, select flap position 1. And before reducing to lower than F speed, select Flap position 2 or 3. But to spare you the calculation i will give you an example with actual speeds.

On an Airbus A318/19/20/21, for a weight of 54 000kg:

Vref= 124kts
Vapp= Vref + 5kts + 1/3 headwind component
F speed= 135kts
S speed= 179kts
Green dot speed= 190kts (Ignore this speed for now)

These speeds are more relevent for flap retracion during takeoff than for the approach if used as a guide.

(If you guys like my explanations and are interested, i will provide more details of various takeoff procedures and proper flap retraction schedules on a seperate post, so just let me know.)

For the approach on the A318/19/20/21, use the following guide:

200kts: Flap pos 1
180kts: Flap pos 2
160kts: Flap pos 3
140kts: Flap pos FULL

Select the respective flap setting 10 kts before reaching the corresponding flap position speed.

For example:
When reducing speed to 200kts in clean CONFIG, select flap pos 1 when passing 210 kts and upon reaching 200kts, maintain speed. Then reduce speed to 180kts and when passing 190kts, set flaps pos 2 and maintain 180kts. Then reduce speed to 160kts and when passing 170kts set flap pos 3 and maintain 160kts. Finally, when reducing to Vapp, select flap pos FULL when passing 150 kts and continue to reduce speed to Vapp.

Now on the issue of when to begin flap extension:

There are several types of approaches.

For a stabalized approach, you want to arrive at the FAF (final approach fix), a point marked by an X or a lighting bolt on the approach chart at which you *usually (again this depends on the chart) intercept the glideslope, at full landing configuration.

As an example: When appoaching R27L at EGLL, the FAF is at DME 7.5nm at 2500ft. If approaching on an Airbus, plan to arrive 5nm before the FAF at CONFIG 2 (Flap pos 2 and gear UP). This means at DME 12.5nm. At 3nm before the FAF (DME 10.5nm) set Gear DOWN. At 2nm before FAF (DME 9.5nm) reduce speed to 160kts and when passing 170kts set flaps pos 3. At 1nm before FAF (DME 8.5nm) reduce speed to Vapp and when passing 150kts set flap pos FULL and maintain Vapp just as you reach the FAF. Now intercept glideslope and maintain Vapp until touchdown.

For Boeing arrive latest 5nm before the FAF at Flaps 5 mainting Vref30 +40kts with gear up. At 3nm before FAF set Gear DOWN. At 2nm before FAF set flaps 20 and reduce speed to Vref30 +20kts. At 1nm before FAF, set flaps 30 and reduce speed to Vapp=Vref30 +5kts + 1/2 headwind component.

As for the decelerated approach, which would be required for example at EHAM, i would eleborate only if anyone is interested.

So, since this reply is getting really long, I hope that this addresses the main question regarding an approach and flap settings.

Like i said, if anyone is interested, i will post a proper tutorial on the various techniques.

Happy landings!


Erm first off I am guessing you copped and pasted that…

Also erm well that’s it you ain’t adding anything to that

Firstly, i didnt copy paste that. If you look at some of my other post you will notice that i usually reply to this kind of question in this manner.

Secondly, it’s comments like yours which really make me wonder why i put in the effort to give such elaborate explanations.


So, flaps must be turned down depending on the speed, when you are at 210kts flaps must be at 5°, 190kts = 10°, 180kts = 15°, 170kts = 25°, 160kts = 30° and 145kts = 40°

Based on the flap settings you are mentioning, i assume you are referring to Boeing. For Boeing use the Vref30 rule. So look up the Vref30 for your Boeing aircraft on a speed table. As stated in my example above, if Vref 30 is 135kts, do the following…
At 215 set flaps 1 and reduce to 195kts
At 195 set flaps 5 and reduce to 175kts etc.

dude ur the Best :) can ya explain how to calcutlate cruise altutide? For example i have 150 nm to dest (altutide that should be) i mean calculations (how to do this)

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MaxSez: I believe the answers to all your tech questions are available in the tutorials, an archive search or a Web Search! The operations of the mind is a wounderous thing. Google is your friend!

Vref is dependent on weight. Make sure you have the correct Vref for your weight.

Again, several factors go into determining the appropriate cruising altitude such as aircraft type, weight, cruising distance, fuel economy, weather etc. One of the main factors that go into deciding your cruising altitude in Infinite Flight, due to the relatively small region size, is the TOD (Top of descent) point, for which there are already tutorials in the forum. In other words, calculate the TOD point for a cruising altitude of your choice and see how much of cruising distance is left for you. If you reverse the calculations for TOD, you can also calculate your distance for the climb. This leaves you with distance climb + distance cruise + distance descent + distance approach. Type TOD into the search bar and you will find plenty of tutorials.

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to get your cruise alt multiply your total distance of your route x 125 For example you have a route thats 150nm multiply that by 125 and it’ll give you 18750ft so best cruise at maybe 18000ft

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@Alexander_Gotze… MaxSez: Exception & accurate by the book responses.
Thanks for taking the time and effort. We are all better for it. Regards

BZ Flag Hoist! “Well Done”

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